Case shift mechanism for typewriting machines



April 3, 11951 J. c. VELTMAN ETAL 2,5425

CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES 5 Sheets-Sheet 1 Fil edAug. 27, 1945 on N r s R w n EL r m H V v M u M Jw April 3, 1951 J. c.VELTMAN ETAL 2,547,895

CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES Filed Aug. 27, 1945 3Sheets-Sheet 2 April 3, 1951 J. c. VELTMAN ETAL CASE SHIFT MECHANISM FORTYPEWRITING MACHINES 3 Sheets-Sheet 3 Filed Aug. 27, 1945 ATTORNEYS.

patented Apr. 3, 1951 CASE SHIFT MECHANISM FOR TYPEWRITING MACHINES JohnC. Vcltman and William '0. Michelson, St. Louis County, Mo., assignorsto The Emerson Electric Mfg. 00., St. Louis, Mo., a, corporation ofMissouri Application August 27, 1945, Serial No. 612,772

10 Claims. (01. 197-73) assembly which are relatively and simultaneouslyshiitable, whereby the upper and lower case type are selectivelypositioned to strike the platen on the printing line.

A further object is to construct a machine of this type in such a manneras to provide a balanced shifting device, whereby positioning thesegment and type bar assembly, and the platen carriage for double caseprinting may be eifected with a minimum of movement and a minimum ofapplication of force, whereby wear upon and distortion of parts issubstantially avoided.

More specifically an object is to cooperatively support and connect theplaten carriage, and segment and type bar assembly in a weight balancedrelation, in order that applied force in accomplishing the shiftingoperation is substantially reduced, resulting in an extremely lightshift key action.

Another more specific object is to reduce the movement necessary ineffecting relative shift of the platen carriage, and segment and typebar assembly, which results in reducing the inertia of the moving parts,thereby reducing impact on the parts on termination of movement, and

thereby minimizing the noise of operation and wear on the parts as aresult of impact at the end of the shift movement.

Another object of the invention is to embody in a typewriting machinehaving the foregoing characteristics an eliicient shift mechanism forthe platen carriage, and segment and type bar assembly, which operatesthe shift with facility and holds the same in proper adjustment forupper and lower case printing, said shift mechanism having lock devices,which are particularly adapted for such purpose.

Another object of the invention is the provision of a type bar operatingmeans that is particularly adapted for quiet and efiicient operation,particularly in combination with the character of shift mechanism abovespecified. Additional advantages of the invention will appear from thefollowing detailed description of the invention taken in connection withthe accompanying drawings, in which:

Fig. 1 is a skeletonized isometric view of such parts of a typewritingmachine as are essential to illustrate the embodiment of the invention,particularly with respect to the type action and relative platencarriage, and segment and type bar assembly shift. In this view theparts are shown in initial position;

Fig. 2 is a similar isometric view further skeletonized to furtherillustrate essential parts in printing position;

Fig. 3 is a view of certain essential parts of the shift mechanism forshifting the platen carriage, and segment and type bar assembly, andalso the upper and lower case locks;

Fig. 4 is a view similar to Fig. 3, in which the parts shown therein arein association with cooperating parts of the printing mechanism;

Fig. 5 illustrates essential parts of the printing mechanism,particularly the key action; and

Fig. 6 is a detail of the stop associated with the universal bar.

As illustrated in the drawings, the machine embodying the invention isshown as including a skeleton frame to be mounted in a conventionalmanner in a main frame (not shown) The skeleton frame comprises rightand left side frame members i and 2, with provision in the form ofspaced openings 3 for mounting and attaching said skeleton frame in themainframe of the machine.

The segment and type bar assembly, and the platen carriage assembly areeach pivotally mounted between said frame members I and 2, the former bypivot mountings at ll, adjacent to the front of the machine, and thelatter by pivot mountings at 5 adjacent to the rear of the machine.

The general structure of the segment and type bar assembly is best shownin Fig. 2, from which it will appear that, as illustrated, it comprisesa 7 segment 6 supported on a transverse plate I,

which extends laterally to each side of the machine. The extremities ofthe plate 1 are bent to form right angle forwardly extending sections 8,each of which is removably connected with a forwardly extending arm 9,which arm pivots on the respective frame members i and 2 on the pivotmember 4.

The lower rail assembly of the platen carriage comprises bracket membersIii, which are cross connected by a tube I A convenient means ofsecuring the extremities of said tube H to the brackets It comprises, as

illustrated, plugs l2 inserted through openings in the respectivebrackets it, said plugs being inserted into the openings in the oppositeends of the tube I l, and then forming a rigid joint by brazing orwelding these parts together. The plugs 12 may be drilled andcountersunk to form bearings for pivot screws l3, which are locked bynuts M in the side members I and 2 of the frame, and which screws,therefore, constitute the pivot mountings for said tube I I, which, inturn, serve as the rocking or pivot supports 5 for the platen carriageassembly.

A lower rail extends transversely of the machine. This rail constitutesthe support for the platen carriage, it being understood that saidcarriage is shiftable transversely thereon in the usual manner Thislower rail rests upon and is secured to brackets I6 positioned adjacentto each end of said rail. The brackets I6, in turn, are releasably andadjustably secured to the top wall of the respective brackets ID,preferably by screws ll that pass through elongated slots IS in angularextensions IQ of the brackets I6, which screws thread into openings insaid top wall of each of the brackets H), as best illustrated in Fig. 2.Since, therefore, the lower rail assembly and the shiftable platencarriage carried thereby are rigid with said brackets H), which, inturn, are pivotally mounted on the pivot screws [3 rigid with the frame,the entire platen carriage support is assembled for rocking movement inrespect to the frame of the machine. As will be later explained, therocking movement of the platen carriage assembly from its normalposition of rest is in an arcuate direction opposite from the movementof the segment and type bar assembly in shifting to and from the, upperand lower case printing positions.

The platen carriage assembly, and the segment and type bar assembly arepivotally interconnected at each side by rocking arms 29. The arms 2!!are connected with the respective brackets I 0, at their rearextremities, by screw and slot connections 2| and, at their frontextremities, are connected by a screw and slot connection 22 with theplates. 9, which constitute the pivoted arms by which the segment andtype bar assembly is supported. The arms 28 constitute rocking arms orlevers, having a pivot connection intermediate their extremities withthe respective side members I and 2 of the frame. A pivot screw 23passing through each frame member and through each of said arms servesto permit the relative rocking movement of said arms in respect of theframe, and thereby a rocking counterbalanced connection between thesegment and type bar assembly, and the platen carriage assembly.

In order to provide for proper alignment and adjustment between theright and left hand rocking connection between these two assemblies tocompensate for any misalignment or distortion in either of them, it ispreferable to form one of said arms in two sections, as illustrated, andto join said sections by a dowel, slot and screw connection 24 arrangedso that a slight angular adjustment between the two sections of the armmay be made.

The segment and type bar assembly is normally held in raised position bya pair of springs 25, the upper ends of which are adjustably supportedin a stationary part of the machine (not shown), and the lower ends areconnected, re-

spectively, with the rear section of the plates or arms 9 of the segmentand type bar assembly frame. These springs serve to resiliently holdsaid plates in such angular position that the forward ends of the rockerarms are raised, thereby tilting the platen carriage assembly forwardlyand downwardly, and the segment and 4 type bar assembly backwardly andupwardly (Fig. 1).

In order to limit the extent of the relative up and down movements ofthe segment and type bar assembly, and the platen carriage assembly,

shift motion stops are provided which, as illustrated, include a pair ofparallel spaced arms 26 secured to the segment plate 7 adjacent to eachend thereof, which cooperate with arms 21, one of which is attachedadjacent to each end of the carriage frame in a position to extendthrough openings in the plate 1 and between said arms 26. The arms 26are formed of material which may be slightly flexed so that said armsmay be adjusted by bending to adjust the limit of the shift movementeither up or down, whereby the relative movement of the segment and typebar assembly, and of the platen carriage assembly will be brought torest for proper alignment of the printing line of the platen for eitherupper or lower case printing.

A series of type bars 28 are pivotally mounted in and supported by thesegment 6 in conventional arrangement. The type bars take the form ofbell crank levers and are preferably pivotally supported on a wire 29seated in a slot formed in the periphery of the segment 6.

It will be understood that the number of type bars 28 preferablyincludes the usual number from forty-two to forty-six, in order toprovide for the usual complement of printing characters arranged on theface of the type 30 in upper and lower case arrangement.

The segment 6 is provided with the usual spacing walls 3| forming slotsthat guide the individual type bars.

In the drawings, only sufficient of the type bars have been illustratedto disclose the arrangement thereof in relation to the structure of thepresent invention.

The key levers 32 for operating the type bars are supported in a keylever bracket 33, which is supported transversely of the machine, and isrigidly connected at its extremities to the inner faces, respectively,of the plates 9 constituting the side members of the frame of thesegment and type bar assembly, whereby the type bars and their operatingmeans move as a unit in shifting movements.

A series of spaced key lever guides 34 in the form of bifurcated lugsform slots in which the inner ends of the key levers 32 are seated. Theinner ends of the key levers 32 are pivoted on a rod 35 passing throughopenings in the levers and seated between the aligned arms of themembers 34. A comb 36 is positioned forwardly of the bracket 33, whichcomb is also supported at its extremities by the plates or arms 9. Thiscomb 33 has a series of vertical slots extending from its bottom edgethrough which the key levers 32 extend and are guided thereby.

A series of intermediate bell crank levers 31 are carried by and pivotedupon a rod 33 supported in the lower section of the key lever bracket33. A series of spaced slots 39 extend upwardly from the bottom of saidbracket and constitute guides in which said levers 3'! rock.

Each of the key levers 32 is formed with an angular arm 32 that extendsdownwardly and rearwardly, the tip of which projects into the respectiveslot 39 and contacts the depending arm of its respective cooperativeintermediate bell crank lever 31 when the selected key lever isoperated.

- contraction of the spring as.

bell crank-levers 31 is connected with its complementary type bar by awire link 4 i.

Th type levers and key levers are held in position of rest (Fig. 1) by aspring 42 attached at one end to the forward arm of each of saidintermediate bell cranks and at the other end to brackets t3 attached tosaid key lever bracket 33. The tension of the springs #2 also serves, byexerting pressure on the front edge of the depend-- ing arms of theintermediate bell cranks against the depending arms of the keylevers, tohold the key levers against a cushion stri 44 supported on the back faceof the vertical wall of the comb 36 above the slots formed therein,which strips cushion the rebound of the key levers.

7 By arranging the ends of the link connection between the intermediatebell cranks and the type levers in line with the pivot point of saidbell cranks, a toggle effect is provided that serves to lock the typebars in their position of rest, and also to prevent rebound of andinterference between the type bars.

' The mechanism for effecting the relative shift of the segment and typebar assembly, and the platen carriage includes shift key levers l5 and46 positioned, respectively, at the right and left of the key board. Therear-ends of said levers are connected by a transverse tie tube 4?. Thelevers 45 and 4e are normally held in raised posi tion by a pair ofspring 45 and 46' attached, respectively, at one end to said levers 45and 46, respectively, and, at their opposite ends, to the top wall ofthe comb 36. The top edge of each of said levers also cushions againstthe extremities I of the cushion strip 44.

The depression of either shift key lever 45 or 46 rocks the shift framcomprising said levers and the tie tube 47, and, through linkage withthe arms 20, lowers the front ends thereof and raises the rear ends,thereby moving the segof the arms 20 include a pair of cushion levers,

oneof which is cooperatively associated with each of the shift keylevers 45 and 46. These cushion levers take the form best shown in Figs.3 and 4, from which it will appear that said levers each include arms 48and t9 forming a bell crank lever pivoted at 50 to one face of verticalarms 5| formed on each of the levers 45 and it at the rear extremitiesthereof. The cushion members each have a third arm indicated at 52, theextremity of which is bent at an angle to form an car 53 which overliesthe top edge of its respective shift lever 55 and 6. The lower extremityof each of the arms at is spring connected to the lower end of saidvertical arms 5! by a spring 54. Each car 53 overlies the upper edge ofits respective associated shift lever and. opposes the Upon downwardmovement of either of said shift levers 45 or 46, the springs 55 rockthearms 43 rearwardly, or

' to the left in Fig. 3.

Each of the arms 29, rearward of its pivot, ha a depending arm 55. Thelower extremities of said arms 55 are each bent inwardly, forming cars56 which extend into the plane of the arms the arms 49 impinge againstthe cars 56 causing the arms 26 to rock and thereby impart the doubleshifting movements to the segment and type assembly,

a shoulder or detent at its lower extremity, which engages with a lug 58which may be attached to a frame brace 58' of the machine. It ispreferably made adjustable by being secured thereto by a binding screw.When a shift lock key lever 59, pivoted on the shift lever 36, isdepressed, the end of said lever rocks against the tendency of a spring69, which connects the lower extremity of the lever 5'1 with the shiftkey lever. The spring 66 normally keeps the detent disengaged upon thenormal depression of the shift key levers, unless the shift lock key 59is also depressed. After the detent is engaged by depressing the lockkey lever 59, the Spring $0 also serves to disengage the detent byslight pressure on one of the shift key levers to move it downwardlyslightly beyond its normal depressed position. This slight additionaldepression of a shift key lever to release the detent is possiblewithout any strain on the parts, because the connection between the rearextremity thereof, and the bell crank levers 68-43 for rocking the arms2%] is a resilient connection because of the springs 54. Thisconstruction, in effect,

provides a cushion connection between the shift tions of the segment andtype bar assembly, and

platen carriage assembly are reversed from the normal or at restposition. In normal position the segment and typ bar assembly is inraised position and the platen carriage is tilted downwardly a alreadyexplained. This is the lower case printing position. When the shiftoccurs the segment and type bar assembly moves downwardly and thecarriage platen is raised, thus, by simultaneous movement of the twoassemblies, each of which makes approximately one half of the combinedmovement, the necessary spacing to align the upper case type to theprinting line is accomplished. Since the movement of each of theassemblies is only approximately one half of the combined movement toeffect the shift, and, since the assemblies counterbalance each other,the inertia of the movement, and impact at the termination of themovement is substantially reduced.

The locking of the assemblies in shifted position, in order to properlyalign the type for upper case printing, is effected by the shift lockingmechanism, as described. that the assemblies be locked in their normalposition to prevent any disalignment of printing in the lower case, andthis lower case lock must be coordinated with the shift mechanism, sothat it may be unlocked when the shift occurs.

The mechanism for effecting the locking of the assemblies in the initialposition includes a bell crank lever associated with each of the rockingbars 20. These bell crank levers each include an arm 62, which extendsforwardly and downwardly, and an arm 63 in the form as illustrated inFig. 3 of the drawings. These levers are pivoted at 64 on a pivotsupport attached, respectively, to the inside face of each of the framemembers I and 2. The forward extremity of each It is also preferable ofthe arms 62 is bent at an angle forming an ear 65, which ears extendinto the plane of the ears 56 formed at the extremities of the arms 55of the rocking bars 26. The arms .62 are normally held in angularadjustment, a illustrated in Fig. 3, in which the ears 65 are in aposition to contact with the ears 56, and thereby prevent the rocking ofthe arms 26 when the parts are in initial position.

The means for maintaining normal adjustment of the arms 62 with the ears65 in locking engagement with the ears 56 comprises a spring 66, one endof which is attached to the lower extremity of the arm 63, and the otherend of which is connected to a spring post carried by the respective oneof the side members i and 2. It will be understood that this position ofthe parts is maintained until the shifting mechanism is operated.

When the shifting mechanism is operated by depression of one of theshift keys 45 or 46, an angular link 6'! pivoted at 68 to the lowerextremity of the respective vertical arms is moved rearwardly. The links51 assume the angle shape best illustrated in Fig. 3, and are supportedand guided in their movements by a screw 69 extending inwardly from eachof the side members I and 2, respectively, said screws projecting intoslots 69 in the upper extremity of the vertical arm of the links 61. Theupper rear edges of the links 6! are formed as cam faces "i0, whichcooperate with fingers ll, which ride on the cam faces 10 in suchrelation that, when the links 61 are moved rearwardly upon depression ofeither of the shift key levers, through the linkage just described, thecars .65 of the arms 62 are moved downwardly against the tendency of thesprings 58, thereby releasing the locks or detents 56-435, so that thearms are free to rock upon continued movement of the shift key levers.This release of the detents occurs on the initial depressive movement ofthe shift key levers, and before the rear edge of the arm 49 of thecushion arms contacts the cars 56 to impart rocking movement to therocker arms 2!). This is because of the fact that there is a slightspace between said arms 69 and the ears 5%, thereby retarding thecontact until the arms 62 are moved downwardly sufiiciently to clear theears 55 from the ears 58.

It is preferable that the fingers ll be made sufficiently flexible inorder to adjust their coni tact tips with the cam faces id to regulatethe timing of the release of the lock and so that, after it has beenreleased, the tip of the fingers H will ride on the cam faces 10 duringfurther depression of the shift key levers, thereby holding the lock outof locking engagement during the period that the shift key lock isoperative to hold the assemblies for upper case printing.

The escapement mechanism and the platen carriage is of conventionalconstruction and, therefore, will not be specifically described. Theoperation of the escapement mechanism,.however, includes certain novelfeatures to adapt it to the shift features of the machine.

This operating mechanism includes a universal bar 12 supportedtransversely of the machine in the rear of the depending arms of thelevers 3i. The universal bar 12 carries at each extremity an arm 13,which arms are, in turn, pivotally mounted at their upper ends on therod 38, that supports the intermediate bell crank levers 31. The arms 13rock in slots formed at the ends of the support for the bank of thelevers 31.

Since the universal bar 12 is adjacent to the depending arms of thelevers 31, whenever anyone of them is rocked upon depression. of a keylever, the universal bar 12 will be rocked rearwardly. In order toadjust the contact and timing of the contact with said universal bar 12,the depending arms of the levers 31 may be bent to adjust the angularrelation of their rear edges to the universal bar.

An adjustable stop limits the return movement of the universal bar 12when the key lever is released. This stop comprises a bracket 14 carriedby each of the arms 13 and positioned to contact the rear face of thekey lever bracket when the universal bar is in its initial position. Thepart of the bracket that makes this contact may carry a cushion 15 inorder to reduce the shock and noise of the contact.

An escapement trip push link 16 is pivoted at its rear end at H to aconventional escapement mechanism generally indicated at E8. The frontend of the link 16 rides in a slot 19 formed in a cross brace. A plateis secured to the top face of the push link 76 to which it is secured inany suitable manner, and an arm Bl formed integrally with said plateextends upwardly at an angle and is located rearwardly of the universalbar I2. The arm 81 is adjusted at an angle, so that the contacting facethereof will remain parallel to the axis of the universal bar in itsupper and lower case position.

It will be apparent that upon each depression of .a key lever, theuniversal bar 12 is rocked in .a rearward arc contacting the arm BI, andthereby moving the escapement trip push link '16 rearwardly, whereby, ina conventional manner, a step by step movement is imparted to the platencarriage. The angular position of the arm 81, as above explained, is ofimportance because the universal bar 12 moves as a unit with the segmentand type bar assembly and, therefore, whenever a shift is made, thepoint of contact of the universal bar changes position vertically in.respect of the arm 8|. This change in relative position of theuniversal bar and the actuating connection with the escapement push linkis compensated for by the adjustment of the angle of the arm 8|..Therefore, irrespective of the relative position of the segment and typebar assembly and the platen carriage assembly, the escapement will betripped at the same point in the movement of the type levers in respectof the platen.

The machine includes the usual spacing bar assembly 82 but, since thisis conventional, it is unnecessary to specifically describe itselements.

The construction and operation of an embodiment of the invention willnow be apparent from the foregoing description amplified by theaccompanying drawings. It will also be obvious that certainmodifications from the illustrative embodiment of the invention may bemade without departure from the scope and principles of the invention.

Having made full disclosure of the invention, what is claimed is:

1. In a typewriting machine including a platen carriage assembly and atype bar assembly, said assemblies being pivoted for rocking movement.in a frame, an interconnection between said assemblies comprisingrocking bars pivotally supported on the frame and pivotally connected toeach of said assemblies, and a shift mechanism for actuating saidrocking bars, whereby said assemblies are moved in opposite arcuatedirections for upper and lower case printing positioning of the typebars.

2. Ina typewriting machine including a platen carriage and a segment andtype bar assembly mounted for upper and lower case printing by movementin opposite directions, an actuator for imparting simultaneous movementto said assemblies, including rocker arms having fixed pivots and arocking pivot connection with each of said assemblies, respectively, keycontrolled lever connections for actuating said rocker arms in onedirection, and spring means actuating said arms in the oppositedirection.

3. In a typewriting machine including a platen carriage and a segmentand type bar assembly mounted in weight balanced relation for u per andlower case printing, rocker arms having fixed pivots and a roc ing pivotconnection with said assemblies, respectively, at'opposite extremitiesthereof, key controlled lever connections for rocking said rocker armsin one direction, and spring means actuating said arms in the oppositedirection.

4. In a typewriting machine including a platen carriage and a segmentand type bar assembly mounted for movement to u per and lower caseprinting positions, an actuator for imparting simultaneous movement tosaid assemblies in opposite directions, including rocker arms havingfixed pivots and rocking pivot connections with said assembliesrespectively, spring means actuating said assemblies to normal position,and 5 a key controlled lever connection for actuating said rocker armsin the other direction in opposition to said spring means.

5. In a typewriting machine, in combination, a frame, a platen carriageassembly pivotally mounted on said frame, a type bar assembly pivotallymounted on said frame, rocking bars pivotally mounted on said frame andpivotally connected to each of said assemblies, and means operativelyassociated with said rocking bars engageable therewith for pivoting thesame in one direction including a resilient connection.

6. In a typewriting machine, in combination, a frame, a platen carriageassembly mounted on said frame, a type bar assembly mounted on saidframe, at least one of said assemblies being pivotally mounted, rockingbars pivotally mounted on said frame and pivotally connected to saidpivotally mounted assembly, and means operatively associated with saidrocking bars engageable therewith for pivoting the same in one directionincluding a resilient connection.

7. In a typewriting machine, in combination, a, frame, a platen carriage.assembly pivotally mounted on said frame, a type bar assembly pivotallymounted on said frame, rocking bars pivotally mounted on said frame andpivotally connected to each of said assemblies, and means operativelyassociated with said rocking bars for pivoting the same in one directionincluding a pivotally mounted shift key lever adjacent each rocking bar,a member pivotally mounted on each pivotally mounted assembly, and meansoperatively associated with said rocking bars for pivoting the same inone direction including a pivotally mounted shift key lever adjacenteach rocking bar, a member pivotally mounted on each shift key leverengageable with its respective rocking bar, and spring means biasingeach shift key lever and its associated member into a predeterminedrelationship.

9. In a typewriting machine, in combination, a frame, a platen carriageassembly pivotally mounted on said frame, a type bar assembly pivotallymounted on said frame, rocking bars pivotally mounted on said frame andpivotallyconnected to each of said assemblies, at least one of saidrocking bars being adjustable, and means operatively associated withsaid rocking bars engaging therewith for pivoting the same in onedirection including a resilient connection.

10. In a typewriting machine, in combination, a frame, a platen carriageassembly pivotally mounted on said frame, a type bar assembly pivotallymounted on said frame, rocking bars pivotally mounted on said frame andpivotally connected to both assemblies, each rocking bar having anextension, a shift key lever pivotally mounted on said frame inassociation with each rocking bar, a bell-crank lever pivotally mountedon each shift key lever including a first arm in 'a plane with therocking bar and a second'arm normally engaging an edge of the shift keylever,

and spring means urging each bell-crank lever into position with itssecond arm in contact with its shift key lever, said first arm of saidbellcrank lever engaging said rocking bar extension to shift saidassemblies of said machine upon file'of this patent:

UNITED STATES PATENTS

